"Medicine is a social science, and politics is nothing else but medicine on a large scale"—Rudolf Virchow

September 26, 2017

After five weeks without a case, the National Environment Agency on its Zika Cases & Clusters page reports two new cases. They appear to scattered cases, not a cluster, and they bring this year's total Zika cases in Singapore to 65. I'll try to find out more details.

The destruction left in Puerto Rico in the path of Hurricane María has pushed the condition of the island back several decades, including when the authorities work to assess the magnitude of the damage, a delegate of the territory has said.

"The devastation of Puerto Rico has put us back about 20-30 years. ... I can't deny that this is a different Puerto Rico from what we saw a week ago," said Jenniffer González, Resident Commissioner of Puerto Rico. "The devastation of property, the collapsed buildings, homeless families, ruins everywhere. The greenery of the island is gone," she added.

Engineers were planning on Sunday to inspect the 90-year-old Guajataca dam, whose reservoir covers 5 square kilometers (2 squar miles) in the northwest of Puerto Rico. The government has report the dam has an enormous crack since María dumped almost 15 inches of rain in the surrounding mountains. They pointed out that "it can collapse at any moment." Residents of the area were evacuated, but began to return to their homes on Sunday after a spillway was opened to relieve pressure on the dam.

Long after the mainland media have lost interest in the disaster, some of the worst consequences will emerge, and many of them will be in the public-health sector.

We can expect a spate of waterborne diseases: leptospirosis, skin infections, diarrhea, hepatitis A and E, typhoid, and maybe even cholera. Add to that untold swarms of mosquitoes, some carrying malaria, dengue, Zika, and chikungunya. As well, mental health issues will slow Puerto Rico's recovery as thousands struggle with PTSD, depression, and anxiety.

The healthcare system will struggle just to deal with such problems, never mind control or eliminate them.

So far, the US government has shown much more concern about uppity black millionaire athletes than about the fate of 3.5 million people living (barely) on American soil.

September 22, 2017

Normally I don't post about an absence of cases, but when I checked the Singapore National Environment Agency's Zika Cases & Clusters page this morning, I saw that it's been five weeks since NEA last reported a case. Whether due to effective vector control or seasonal factors, this long pause is encouraging.

September 21, 2017

About three quarters of counties on the US mainland have suitable environments for harboring Aedes aegypti and Aedes albopictus mosquitoes, two species capable of spreading viruses that cause Zika, dengue, chikungunya, and yellow fever infection, a team led by the Centers for Disease Control and Prevention (CDC) reported today.

The authors of the new report, published today in the Journal of Medical Entomology, said they generated maps using predictive models that combine mosquito records from individual counties that were published earlier this year with historical surveillance data reaching back to 1960 and county-level climate data going back to 1980. A problem with the earlier county-based report was gaps or differences in mosquito surveillance, which probably underestimated the areas that could support Aedes populations, they said.

Rebecca Eisen, PhD, a research biologist with the CDC's Division of Vector-Borne Diseases and senior author of the study, said in an Entomological Society of America press release, "These maps show CDC's best estimate of the potential range of Ae. aegypti and Ae. Albopictus." She added that the maps show where the species could survive and reproduce if introduced during the months when mosquitoes are locally active.

Estimates identify favorable climate areas

For Ae aegypti, 71% of counties in the contiguous states are suitable, with the range covering much of the eastern part of the country south of the Great lakes, plus parts of several southwestern states. The group also found that for Ae albopictus, about 75% of counties are suitable, with the range extending further into the northeast and more limited in the southwest.

Zika virus transmission dynamics in urban environments follow a complex spatiotemporal pattern that appears unpredictable and barely related to high mosquito density areas. In this context, human activity patterns likely have a major role in Zika transmission dynamics. This paper examines the effect of host variability in the amount of time spent outdoors on Zika epidemiology in an urban environment.

Methodology/Principal findings

First, we performed a survey on time spent outdoors by residents of Miami-Dade County, Florida. Second, we analyzed both the survey and previously published national data on outdoors time in the U.S. to provide estimates of the distribution of the time spent outdoors. Third, we performed a computational modeling evaluation of Zika transmission dynamics, based on the time spent outdoors by each person.

Our analysis reveals a strong heterogeneity of the host population in terms of time spent outdoors–data are well captured by skewed gamma distributions. Our model-based evaluation shows that in a heterogeneous population, Zika would cause a lower number of infections than in a more homogenous host population (up to 4-fold differences), but, at the same time, the epidemic would spread much faster.

We estimated that in highly heterogeneous host populations the timing of the implementation of vector control measures is the major factor for limiting the number of Zika infections.

Conclusions/Significance

Our findings highlight the need of considering host variability in exposure time for managing mosquito-borne infections and call for the revision of the triggers for vector control strategies, which should integrate mosquito density data and human outdoor activity patterns in specific areas.

September 03, 2017

Vaccine giant Sanofi Pasteur has quietly pulled the plug on its Zika vaccine project, a move that underscores how difficult it may be at this stage to develop a vaccine against the virus.

The company announced the move in a statement posted on its website at 3 p.m. Friday, pointing to a decision by a federal funding body to scale back spending on Zika-related research. Sanofi said BARDA — the Biomedical Advanced Research and Development Authority, an arm of the Department of Health and Human Services — informed the company in mid-August that it was reducing its financial assistance for Sanofi’s Zika vaccine project.

“Consequently, Sanofi does not intend to continue development of, or seek a license from, the Walter Reed Army Institute of Research for the Zika vaccine candidate at this time,” the company stated.

While a number of experimental Zika vaccines are at various stages in clinical testing, Sanofi was the only major pharmaceutical company working on a vaccine for the virus with a near-term market goal.

A spokeswoman said Saturday that Jon Heinrichs — the Sanofi executive who was spearheading the Zika project — was not available for an interview.

Neither was BARDA director Rick Bright, though he commented briefly by email about the agency’s shift in funding plans.

“Zika remains a public health threat, and BARDA plans to continue working with industry partners including Sanofi on developing Zika vaccines and diagnostics to make them available commercially as quickly as possible,” Bright told STAT. “The specific activities of development projects often change based on a variety of technical and epidemiological factors.”

Commercial concerns

Sanofi was the target of a lot of negative press earlier this year when a number of federal and state lawmakers raised concerns about Sanofi’s contract with Walter Reed, where federal government scientists designed the vaccine.

They complained that a vaccine that had been created with taxpayer funding might be priced out of the reach of Americans. Those statements led to a bruising and public back-and-forth about the company’s pricing intentions.

With Zika out of the headlines and infections in the Americas seemingly at very low levels, the company’s decision to stop work on the project is not surprising. The financial prospects for a Zika vaccine are unclear at this point.

Two years ago, doctors in cities in the northeast of Brazil began to see the first startling cases of what today is called congenital Zika syndrome (CZS) – babies born with a range of severe birth defects, including small, misshapen heads (microcephaly). The doctors suspected – and laboratory work soon proved – that the damage was caused by a Zika virus infection contracted while the mothers were pregnant.

In a matter of weeks, Brazil declared the phenomenon a national health emergency – and, as international alarm at what was unfolding grew, the World Health Organization declared it a global one less than three months later. The rest of Brazil, then the rest of the Americas, braced for disaster, as a newly vicious strain of the Zika virus was carried by mosquitoes inexorably north.

The disaster didn't come – to the immense relief of pregnant women and governments across the region. Babies in other places have since been born with CZS: in Colombia, in Puerto Rico and the continental United States, and in Southeast Asia. But the phenomenon is relatively rare – in most places, it seems, about 7 per cent of pregnant women who contract Zika will have affected babies.

Yet, in northeastern Brazil, back in 2015, the rates of birth defects appear to be manyfold higher, and a much greater proportion of the affected babies have more severe clinical presentations such as microcephaly. The difference is stark. And it only happened once: There was another wave of Zika, a year later, but there was no second spike of affected babies.

And while epidemiologists and public-health experts in Brazil are glad the CZS crisis was not replicated on the same devastating scale – the fact is that, two years later, no one knows why not – and no one can explain what happened in 2015.

This is the kind of baffling public-health puzzle the AIDS virus represented in the early 1980s. There have been some significant scientific gains on Zika: There is a vaccine for the virus already in trials and scientists have mapped out much of the path of how Zika destroys fetal neural development. But when it comes to the mystery of northeastern Brazil, there are mostly just big questions, and a range of best guesses, with researchers facing immense obstacles in trying to prove one theory or another.

The challenge has been compounded by the political and economic crises that continue to grip Brazil: It has shrunk research budgets and paralyzed ministries and departments responsible for trying to unravel this mystery.

U.S.-based surveys conducted throughout 2016 have shown high levels of awareness of the Zika virus outbreak, moderate levels of concern about Zika, and low levels of knowledge about how Zika is transmitted.

What is added by this report?

Zika-related awareness, beliefs, and actions among residents of the U.S. Virgin Islands, who are not included in U.S.-based surveys, were assessed in interviews of pregnant women and community members. Multiple respondents reported hearing that Zika virus is transmitted by mosquitoes and causes microcephaly in babies. Fewer mentioned hearing about sexual transmission of Zika virus or what actions to take to prevent infection. Most respondents reported Zika virus as a serious concern although there were varying levels in perceptions of susceptibility and protective actions taken. Most pregnant women reported receiving interventions offered to them and most community members expressed support for several vector control approaches.

What are implications for public health practice?

The feedback from these interviews helped the U.S. Virgin Islands Department of Health identify information gaps that can be addressed through communication, education, and community engagement. Gathering feedback about key aspects of a response effort from community members is vital to ensure that interventions reach them and are translated into effective prevention programs.

August 30, 2017

Public health researchers who focus on long-range impacts watched the catastrophe with disbelief. Before the flood, Houston already had problems. Flood waters seemed to only exacerbate potential dangers.

“Words just can’t describe it,” said Garrett Sansom, an environmental health scientist at Texas A&M University. “We’ve been trying to wrap our heads around a unified response as researchers, but also the communities we work with have been hit the hardest.”

Houston was already affected by inequality and healthcare disparities. The Manchester neighborhood in Houston is what Samson described as a “classic environmental justice” area – a Latino neighborhood on the Houston shipping channel where petrochemical plants surround houses and most people speak Spanish.

“Barium is ubiquitous in the area because of refineries, as well as arsenic and mercury,” said Sansom. “All of that is going to be in potential of coming into contact with humans. There’s sort of the complex chemical mixture.”

Wildlife can also become a sudden danger. Standing water left after the flood recedes will leave an ideal breeding ground for mosquitoes – which were already a pest in Houston.

“I can’t emphasize the vector-borne disease issue,” said Dr Gerald Parker, as associate dean at Texas A&M who served for 36 years in disaster response for the federal government. Mosquito-borne diseases, he said, are “just something I’m really concerned about.”

Zika captures the most headlines of any mosquito-spread diseases, but it’s far from the only one. The same Houston-endemic mosquitoes transmit dengue and chikungunya, infections characterized by fever. Other mosquito species spread West Nile virus, which can be dangerous for the elderly and health compromised.

Flood waters have also delivered fire ants to front doors, and Sansom warned flooded houses can become a home for venomous snakes such as water moccasins.

Water-borne and person-to-person infections can also easily spread after a disaster. Overwhelmed sewer systems bring people into contact with disease-spreading bacteria. Stomach illnesses are common following floods, public health officials said.

“The main thing that people have to watch out for is gastrointestinal infections,” said Dr Rick Watkins, an infectious disease doctor who studied waterborne diseases following Hurricane Katrina. “Those are going to be because of the disruption of the sewage systems and, unfortunately, the drinking water is going to be contaminated.”

About 300 public water systems were in the path of tropical storm Harvey, according to the US Environmental Protection Agency. Texas environmental protection officials said it is still unclear which systems might be contaminated.

Microcephaly is an important sign of neurological malformation and a predictor of future disability. The 2015–16 outbreak of Zika virus and congenital Zika infection brought the world's attention to links between Zika infection and microcephaly. However, Zika virus is only one of the infectious causes of microcephaly and, although the contexts in which they occur vary greatly, all are of concern.

In this Review, we summarise important aspects of major congenital infections that can cause microcephaly, and describe the epidemiology, transmission, clinical features, pathogenesis, management, and long-term consequences of these infections. We include infections that cause substantial impairment: cytomegalovirus, herpes simplex virus, rubella virus, Toxoplasma gondii, and Zika virus. We highlight potential issues with classification of microcephaly and show how some infants affected by congenital infection might be missed or incorrectly diagnosed.

Although Zika virus has brought the attention of the world to the problem of microcephaly, prevention of all infectious causes of microcephaly and appropriately managing its consequences remain important global public health priorities.